Lubricating oil feeding mechanism in a swash type compressor

ABSTRACT

Lubricating oil feeding mechanism has an oil-collecting recess and an oil-supplying groove formed on the wall of the housing. The oil-collecting recess connects a gap defined between the through hole and the bolt to the oil-supplying groove, the gap being in the upper position with respect to a sliding part to be lubricated in the housing in an operating state of the mounted compressor. The oil-collecting recess extends from the gap in the circumferential direction of the drive shaft, and the oil-supplying groove upwardly extends toward the oil-collecting recess. The oil-supplying groove is arranged so as to guide lubricating oil to the sliding part. Lubricating oil adhered on the bolt can be collected to the oil-collecting recess via the gap, and is fed to the sliding part through the oil-supplying groove. Therefore, a large amount of lubricating oil in a swash plate chamber can be utilized to lubricate the sliding part.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a swash type compressor and, moreparticularly, to an improved lubricating oil feeding mechanism for suchcompressors.

2. Description of the Related Art

In general, swash type compressors with variable or fixed displacementmechanism have a swash plate chamber to arrange a swash plate therein.The compressors also have a bearing for supporting a drive shaft coupledto the swash plate and a shaft seal for preventing refrigerant gas inthe swash plate chamber from leaking outside. The bearing and the shaftseal are to be lubricated by lubricating oil contained in refrigerantgas in the swash plate chamber.

Japanese Utility Model Application Laid-Open Publication No. 57-112082discloses a swash type compressor having a cylinder block formingcylinder bores and a swash plate chamber therein; a drive shaftrotatably supported on the cylinder block via radial bearings; a swashplate coupled to the drive shaft and arranged in the swash platechamber; and pistons slidably arranged in the cylinder bores andoperatively engaged with the swash plate via shoes in FIGS. 5 and 6thereof. Further, the compressor, for lubricating the radial bearings,has passages formed on the cylinder block for arranging bolts therein,the passages being used for connection between the swash plate chamberand suction chambers; oil-collecting recesses formed on end faces of theswash plate chamber, the recesses being connected to the passages; andapertures formed in the cylinder block, the apertures being connected tothe recesses. In such a compressor, lubricating oil flowing on the endfaces is trapped by the recesses and guided to the radial bearingthrough the apertures.

Furthermore, Japanese Patent Application Laid-Open Publication No.2005-171851 discloses a variable displacement swash type compressorhaving a front housing forming a shaft seal chamber therein; anoil-guiding passage formed on the front housing, the oil-guiding passageincluding an oil-guiding groove and a recess connected to theoil-guiding groove, the recess having a side wall; a aperture formed inthe front housing, the aperture connecting the shaft seal chamber to theoil-guiding groove; a wall formed on the front housing, the wallprotruding from the bottom surface of the recess so as to divide therecess into small areas in FIGS. 1 and 2 thereof. In such a compressor,lots of lubricating oil flowing along the front housing inside of thecompressor is trapped by the recess and guided to the shaft seal chamberthrough the oil-guiding groove and the aperture due to the fact thatsome lubricating oil colliding with the side wall is collected by onearea of recess, while the other lubricating oil going beyond the wall iscollected by the other area of recess.

In the conventional arts as mentioned above, some of the solutions aredisclosed to conduct lubricating oil in the swash plate chamber toward asliding part to be lubricated such as the shaft seal or the bearing.These solutions are, however, not sufficient in view of utilizinglimited lubricating oil in the swash plate chamber more efficiently toobtain sufficient lubrication of the sliding part in the compressor. Ingeneral, lubricating oil in the swash plate chamber is splashed andcirculated therein by the rotation of the swash plate during compressoroperation. In such a state some amount of lubricating oil adheres to aside wall of the swash plate chamber, and then, flows downwardly alongthe side wall due to its own weight. The compressors as mentioned aboveare compressors which have mechanism for the collection of suchlubricating oil flowing downwardly along the side wall. In thisconnection, the inventors have found a particularity of lubricating oildistribution in the swash plate chamber that a large amount oflubricating oil in the swash plate chamber tends to adhere to boltsarranged through the swash plate chamber to fasten each housingelements, due to the fact that it is easy for lubricating oil splashedand circulated by the rotation of the swash plate to collide with thebolts arranged in the area of the circulation of lubricating oil. In thecompressors as mentioned above, such the lubricating oil adhered on thebolts cannot positively be used for the lubrication of the sliding part.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a lubricating oilfeeding mechanism in a swash type compressor, which can efficientlyconduct a large amount of lubricating oil in the swash plate chamber tothe sliding part in the compressor so that the sliding part can becomemore reliable.

In accordance with an aspect of the present invention, there is provideda lubricating oil feeding mechanism in a swash type compressor having ahousing comprising a plurality of housing elements, in which a swashplate chamber is formed for receiving a swash plate therein, and whichdefines a cylinder bore therein; a plurality of bolts arranged throughthe swash plate chamber and in through holes formed on a wall of thehousing for fastening the housing elements to form the housing; a driveshaft rotatably supported by the housing, the drive shaft being coupledto the swash plate; a piston accommodated in the cylinder bore so as todefine a compression chamber in the cylinder bore, the piston beingcoupled to the swash plate; and a suction chamber and a dischargechamber formed in the housing respectively, both being connectable tothe compression chamber. The lubricating oil feeding mechanism comprisesan oil-collecting recess and an oil-supplying groove formed respectivelyon a side wall surface being defined on the wall of the housing andfacing the swash plate chamber. The oil-collecting recess connects a gapdefined between the through hole and the bolt to the oil-supplyinggroove, the gap being in the upper position with respect to a slidingpart to be lubricated in the housing in an operating state of themounted compressor. The oil-collecting recess extends from the gap inthe circumferential direction of the drive shaft. The oil-supplyinggroove extends upwardly toward the oil-collecting recess. Theoil-supplying groove is arranged so that oil guided along theoil-supplying groove is led to the sliding part.

In the aspect of the present invention, lubricating oil adhered on thebolts is collected to the gap defined between the through holes and thebolts due to its own weight. The oil-collecting recess collects not onlylubricating oil flowing downwardly on the side wall surface of thehousing but also such lubricating oil gathered in the gap, and thenfeeds the lubricating oil collected therein by the oil-supplying groove.Lubricating oil guided to the oil-supplying groove is, then, led to thesliding part. Therefore, a large amount of lubricating oil in the swashplate chamber can efficiently be conducted to the sliding part of thecompressor. Namely, this positive utilization of lubricating oil in theswash plate chamber enables the sliding part to be come more reliableduring compressor operation.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will be apparent from thefollowing description taken in connection with the accompanying drawingwherein:

FIG. 1 is a longitudinal cross-sectional view, taken along the line A-Aof FIG. 2, of a variable displacement compressor to which the presentinvention is applied, as a first embodiment thereof;

FIG. 2 is a cross-sectional view taken along the line B-B of FIG. 1;

FIG. 3 is a cross-sectional view taken along the line C-C of FIG. 2;

FIG. 4 is a cross-sectional view of a variable displacement compressorshowing a second embodiment of the present invention;

FIG. 5 is a cross-sectional view of a variable displacement compressorshowing a third embodiment of the present invention;

FIG. 6 is a cross-sectional view of a variable displacement compressorshowing a fourth embodiment of the present invention;

FIG. 7A is a partial and schematic view of lubricating oil feedingmechanism showing another embodiment of the present invention.

FIG. 7B is a partial and schematic view of lubricating oil feedingmechanism showing another embodiment of the present invention.

FIG. 7C is a partial and schematic view of lubricating oil feedingmechanism showing another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1, 2 and 3, a first embodiment of the presentinvention is described hereinafter. FIG. 1 shows a variable displacementswash plate type compressor whose housing comprises a front housing 1, acylinder block 2, a rear housing 3 and a valve plate unit 4 interposedbetween the cylinder block 2 and the rear housing 3. These housingelements 1, 2, 3 and 4 are fastened together as one body with aplurality (nine) of bolts 5 as shown in FIG. 2. The front housing 1 andthe cylinder block 2 define a swash plate chamber 12 as a controlchamber therebetween.

The front housing 1 and cylinder block 2 have a central axial boreformed therein respectively for receiving a drive shaft 6 which isrotatably supported by a pair of radial bearings 7 and 9 provided in thecentral axial bore, wherein one end of which is further supported by athrust bearing 8 provided in the central axial bore of the cylinderblock 2. Furthermore, in the central axial bore, a shaft seal 11 isdisposed between the drive shaft 6 and the front housing 1 in a certainspace 10 outside the radial bearing 9 and prevents refrigerant gas inthe swash plate chamber 12 from leaking outside. The drive shaft 6 isengaged with engine E as a motor of the vehicle at the other end thereofand can be driven by the engine E.

There are disposed a lug plate 15 and a swash plate 16 coupled to thelug plate 15 through a hinge mechanism 17 in the swash plate chamber 12.The lug plate 15 is fixed on the drive shaft 6 and is supported on aside wall 13 of the front housing 1 via a thrust bearing 14 providedtherebetween. The swash plate 16 is supported on the drive shaft 6slidably and movably in the direction along the axis thereof and isconnected to the hinge mechanism 17 to be allowed to incline withrespect to the axis of drive shaft 6. Therefore, the swash plate 16rotates together with the lug plate 15 when the drive shaft 6 rotates,while the inclination of the swash plate 16 changes in accordance withthe pressure control of the swash plate chamber 12. It is here notedthat each of the radial bearings 7 and 9, the thrust bearings 8 and 14,and the shaft seal 11 represents a sliding part in accordance with thedefinition of the present invention.

As can be seen from FIG. 2, the cylinder block 2 has nine cylinder bores18 formed therein. The same number of single headed pistons 19 isslidably accommodated in the cylinder bores 18 respectively. Each piston19 is engaged with the swash plate 16 at the outside thereof via a pairof shoes 20. Therefore, the rotation motion of the drive shaft 6 isconverted into the reciprocation motion of pistons 19 through the swashplate 16 and the shoes 20.

A compression chamber 21 is defined in the cylinder bore 18 on the rightside of FIG. 1 in association with piston 19 and the valve plate unit 4.There are provided a suction chamber 22 as a suction pressure region anda discharge chamber 23 as a discharge pressure region respectively inthe rear housing 3.

As each piston 19 moves from the top dead center to the bottom deadcenter in the associated cylinder bore 18, the refrigerant gas in thesuction chamber 22 is sucked up into the compression chamber 21 throughan associated suction port 24 formed on the valve plate unit 4, causingan associated suction valve 25 disposed in the valve plate unit 4 toflex to an open position. Further, as each piston 19 moves from thebottom dead center to the top dead center in the associated cylinderbore 18, the refrigerant gas in the compression chamber 21 is compressedto a certain pressure level and is discharged out into the dischargechamber 23 through an associated discharge port 26 formed on the valveplate unit 4, causing an associated discharge valve 27 disposed in thevalve plate unit 4 to flex to an open position.

The suction chamber 22 is connected with the swash plate chamber 12 by arelease passage 28 which is formed in the cylinder block 2 and the valveplate unit 4. The discharge chamber 23 is connected with the swash platechamber 12 by a supply passage 29 which is formed in the cylinder block2, the valve plate unit 4 and the rear housing 3. The supply passage 29is regulated by a displacement control device 31 including a controlvalve 30, which is accommodated in the rear housing 3.

Therefore, the pressure in the swash plate chamber 12 can be controlledby the control valve 30. When the control valve 30 opens the supplypassage 29, the refrigerant gas in the discharge chamber 23 is permittedto flow into the swash plate chamber 12 via the supply passage 29 and tomake the pressure in the swash plate chamber 12 be high. On the otherhand, when the control valve 30 closes the supply passage 29, therefrigerant gas in the discharge chamber 23 is not permitted to flowinto the swash plate chamber 12 via the supply passage 29. Thus, therefrigerant gas in the swash plate chamber 12 flows out to the suctionchamber 22. This makes the pressure in the swash plate chamber 12 below. The inclination of the swash plate 16 is determined by the pressuredifference between the pressure in the swash plate chamber 12 and thepressure in the compression chamber 21. Therefore, the displacement ofthe compressor can be controlled based on the inclination of swash plate16.

As shown in FIG. 1, when the pressure in the swash plate chamber 12 isrelatively low, the swash plate 16 can be at a maximum inclination angleas indicated by a double dotted line in the state that the swash plate16 abuts on the lug plate 15. On the other hand, when the pressure inthe swash plate chamber 12 is relatively high, the swash plate 16 can beat a minimum inclination angle as indicated by a solid line.

As shown in FIG. 1, the bolt 5 has a head portion 501 a, a shank portion501 b, and a threaded end portion 501 c. The head portion 501 a issealingly engaged with the front housing 1, while the threaded endportion 501 c is threaded into a threaded bore formed in the rearhousing 3. The shank portion 501 b is arranged so as to extend through afirst bore 32 as a through hole which is formed in the front housing 1,the swash plate chamber 12, a second bore 33 as the through hole whichis formed in the cylinder block 2, and a third bore 4 a which is formedin the valve plate unit 4. As can be seen from FIG. 2, each through holeis arranged to be in between the cylinder bores 18. The first bore 32has a diameter wider than the diameter of the shank portion 501 b suchthat a gap 321 is defined therebetween. In this preferred embodiment,although the gap 321 is defined by the shank portion 501 b and the firstbore 32 the gap 321 may be defined between the shank portion 501 b and afirst bore having a different shape from the first bore 32. In addition,a first bore may be shaped into other cross-sectional configurationsthan circular cross-sectional configurations.

As shown in FIGS. 2 and 3, the side wall 13 has a side wall surface 34which faces the swash plate chamber 12. Oil-collecting recesses 35, 36and oil-supplying grooves 37, 38 are formed on the side wall surface 34.The oil-collecting recess 35 is connected with a gap 321 a defined bythe shank portion 501 b of the bolt 5 a, while the oil-collecting recess36 is connected with a gap 321 b defined by the shank portion 501 b ofthe bolt 5 b which is adjacent to the bolt 5 a and at a backwardposition in the rotational direction of the drive shaft 6 with respectto the bolt 5 a. These gaps 321 a, 321 b are in the upper position withrespect to the shaft seal 11 as the sliding part to be lubricated in thehousing in an operating state of the compressor mounted on the vehicle.

The oil-collecting recess 35 is formed so as to have an arched shape andextends from the gap 321 a in the rotational direction of the driveshaft 6 as indicated by an arrow shown in FIG. 2. A sub oil-collectingrecess 39 is formed on the side wall surface 34 and is connected withthe gap 321 a in the opposite side of the oil-collecting recess 35 withrespect to the gap 321 a. The sub oil-collecting recess 39 is formed soas to have an arched shape and extends, with a relatively short lengthas compared with the oil-collecting recess 35, from the gap 321 a in theopposite direction of the rotational direction of the drive shaft 6.

On the other hand, the oil-collecting recess 36 is formed so as to havean arched shape and extends from the gap 321 b in the opposite directionof the rotational direction of the drive shaft 6. A sub oil-collectingrecess 40 is formed on the side wall surface 34 and is connected withthe gap 321 b in the opposite side of the oil-collecting recess 36 withrespect to the gap 321 b. The sub oil-collecting recess 40 is formed soas to have an arched shape and extends, with a relatively short lengthas compared with the oil-collecting recess 36, from the gap 321 b in therotational direction of the drive shaft 6. Further, the oil-collectingrecesses 35, 36 and the sub oil-collecting recesses 39, 40 extend sothat their width is substantially the same as the diameter of the firstbore 32 along the longitudinal direction thereof.

The oil-supplying groove 37 extends in the radial direction of the driveshaft 6 and is, at the top end thereof, connected to a forward positionof the oil-collecting recess 35 in the rotation direction of the driveshaft 6. As can be seen in FIG. 3, the oil-supplying groove 37 is formeddeeper than the oil-collecting recess 35 to promote oil flow from theoil-collecting recess 35 to the oil-supplying groove 37. On the otherhand, the oil-supplying groove 38 extends in the radial direction of thedrive shaft 6 and is, at the top end thereof, connected to a backwardposition of the oil-collecting recess 36 in the rotation direction ofthe drive shaft 6. Likewise, the oil-supplying groove 38 is formeddeeper than the oil-collecting recess 36 to promote oil flow from theoil-collecting recess 36 to the oil-supplying groove 38. As shown inFIGS. 1 and 2, the side wall 13 has oil-supplying apertures 41, 42 whichconnect the swash plate chamber 12 to the certain space 10. Theoil-supplying groove 37, 38 are, at the bottom thereof, connected withthe oil-supplying apertures 41, 42 respectively so that lubricating oilguided along the oil-supplying grooves 37, 38 and the oil-supplyingapertures 41, 42 is led to the radial bearing 9 and the shaft seal 11defined as the sliding part.

As shown in FIG. 1, there is provided a refrigerant circuit 43incorporating the above-mentioned compressor in vehicle airconditioners. It is here noted that the refrigerant gas such as anatural refrigerant gas like CO₂ gas (carbon dioxide) or freon gas isused in the compressor. The refrigerant circuit 43 has, in turn, a gaspressure reducing valve 44 connected to the discharge chamber 23, acondenser 45, a receiver 46, an expansion valve 47, and an evaporator 48connected to the suction chamber 22. There is provided a pressure sensor49 in a conduit between the condenser 45 and the receiver 46. Thepressure sensor 49 detects the pressure in the conduit and issuessignals relating to the detected pressure to a controller (not shown).The controller is also connected to the displacement control device 31and controls it.

The operation of the compressor having the lubricating oil feedingmechanism will now be described.

When the drive shaft 6 of the compressor is rotated by the engine E, theswash plate 16 is also rotated for receiving rotational power of thedrive shaft 6 through the lug plate 15 and the hinge mechanism 17.Rotation of the swash plate 16 gets each of the piston 19 to bereciprocated in the cylinder bore 18 so that refrigerant gas in thesuction chamber 22 is sucked into the compression chamber 21, and thenrefrigerant gas in the compression chamber 21 is compressed and isdischarged into the discharge chamber 23.

The hinge mechanism 17 serves as an agitator so as to agitate or splashlubricating oil contained in refrigerant gas in the swash plate chamber12 while the swash plate 16 is rotating because the hinge mechanism 17corresponds to a portion which partially protrudes from the lug plate 15and the swash plate 16. When the swash plate 16 is rotated, the hingemechanism 17 makes lubricating oil stayed in/under the swash platechamber 12 be circulated therein. By that agitation, some amount of thecirculated lubricating oil in the swash plate chamber 12 adheres to theside wall 13, an inner peripheral surface of the swash plate chamber 12and an end face of the cylinder block 2.

On the other hand, however, a large amount of lubricating oil in theswash plate chamber 12 tends to adhere on the bolts 5 arranged throughthe swash plate chamber 12, due to the fact that it is easy forlubricating oil splashed and circulated by the rotation of the hingemechanism 17 to collide with the bolts 5 as an obstacle in the directionof the circulation of lubricating oil. The lubricating oil adhered onthe bolts 5 largely drops downwardly toward the bottom of the swashplate chamber 12 directly due to its own weight. The lubricating oiladhered on the bolt 5, a position of which is located near the sidewall, tends to drop into the gap 321 due to surface tension.

Lubricating oil gathered in the gaps 321 a, 321 b flows by its ownweight and is led to the oil-collecting recesses 35, 36. Besides,lubricating oil adhered on the side wall surface 34 of the side wall 13flows downwardly by its own weight and a part of that is collected bythe oil-collecting recesses 35, 36, the sub oil-collecting recesses 39,40 and oil-supplying grooves 37, 38 efficiently due to theirconfiguration. Here, lubricating oil gathered in the sub oil-collectingrecesses 39, 40 is led to the oil-collecting recesses 35, 36 through thegaps 321 a, 321 b respectively. After being collected into theoil-collecting recesses 35, 36, lubricating oil flows in thecircumferential direction of the drive shaft 6 along the oil-collectingrecesses 35, 36 by its own weight. The oil-supplying grooves 37, 38 areformed further deeper than the oil-collecting recesses 35, 36 wherebyfeeding lubricating oil from the oil-collecting recesses 35, 36 to theoil-supplying groove 37, 38 can be ensured.

In addition, the revolution of the hinge mechanism 17 with the rotationof the swash plate 16 makes not only lubricating oil in the swash platechamber 12 be splashed or be circulated but also lubricating oil adhereon the side wall surface 34, in the oil-collecting recesses 35, 36, andin the sub oil-collecting recesses 39, 40 as well as lubricating oilgathered in the gap 321 a, 321 b flow in the rotational direction of thedrive shaft 6 by gas streams accompanied with the circulation oflubricating oil in the swash plate chamber 12. For this reason,lubricating oil adhered on the side wall surface 34 and gathered in thegaps 321 a, 321 b can easily be collected in the oil-collecting recesses35, 36 and the sub oil-collecting recesses 39, 40. Especially, when thedrive shaft 6 is rotated in the direction as indicated by the arrowshown in FIG. 2, lubricating oil in the oil-collecting recess 35 andlubricating oil below the oil-collecting recess 35 can easily be fed tothe oil-supplying groove 37 as compared with that in the oil-collectingrecess 36. In contrast to that, in case where the drive shaft 6 isrotated in the opposite direction of the rotational direction asindicated by the arrow shown in FIG. 2, lubricating oil in theoil-collecting recess 36 and lubricating oil below the oil-collectingrecess 36 can easily be fed to the oil-supplying groove 38 as comparedwith that in the oil-collecting recess 35.

Lubricating oil supplied in the oil-supplying grooves 37, 38 are furtherguided to the certain space 10 through the oil-supplying apertures 41,42 so that the certain space 10 can be filled with a large amount oflubricating oil. Therefore, the shaft seal 11 can sufficiently belubricated. Also, the radial bearing 9 can sufficiently be lubricated.This makes the sliding part such as the shaft seal 11 and the radialbearing 9 much more durable.

The first embodiment of the present invention has the followingadvantages.

The oil-collecting recesses 35, 36 is connected with the gap 321 a, 321b so that lubricating oil collided with the bolts 5 in the route of thecirculation of lubricating oil caused by the revolution of the hingemechanism 17, a portion of which is located near the gap 321 a, 321 bcan effectively be collected into the oil-collecting recesses 35, 36.Therefore, such the lubricating oil adhered on the bolts 5 canpositively be utilized for lubrication of the sliding part.

The oil-collecting recesses 35, 36 are arranged extending in thecircumferential direction of the drive shaft 6. Therefore, lubricatingoil gathered in the gaps 321 a, 321 b and adhered on the side wallsurface 34 can efficiently be collected by the oil-collecting recesses35, 36. As a result, lubrication for the sliding part can be ensured.

The oil-supplying groove 37 is connected to the oil-collecting recess 35at the forward position in the rotational direction of the drive shaft 6with respect to the gap 321 a. Due to the revolution of the hingemechanism 17 with the rotation of the swash plate 16, lubricating oilflows in the rotational direction of the drive shaft 6 led by gasstreams accompanied with the circulation of lubricating oil in the swashplate chamber 12, thus, lubricating oil in the oil-collecting recess 35and lubricating oil below the oil-collecting recess 35 can more easilybe fed to the oil-supplying groove 37.

While the oil-collecting recess 35 is arranged extending downwardly fromthe gap 321 a in the rotational direction of the drive shaft 6, theoil-collecting recess 36 is arranged extending downwardly from the gap321 b in the opposite direction of the rotational direction of the driveshaft 6. Therefore, lubricating oil collecting ability of the bolts 5can be ensured due to the own weight of lubricating oil.

The lubricating oil feeding mechanism comprising the oil-collectingrecesses 35, 36 and the oil-supplying grooves 37, 38 can easily beprovided due to the fact that a recess and a groove have only to beformed on the side wall 13.

The present invention may be alternatively embodied in the followingforms:

FIG. 4 shows a lubricating oil feeding mechanism according to a secondembodiment. In the second embodiment, component parts and elementscorresponding to those of the above first embodiment are indicated byidentical reference numerals, and a description thereof is omitted.There is provided an oil-collecting recess 50 formed on the side wall13, the oil-collecting recess 50 extending from the gap 321 a in therotational direction of the drive shaft 6. The oil-collecting recess 50has a connection groove 51 as a part thereof, the connection groove 51connecting the gap 321 a to the rest of the oil-collecting recess 50.The width of the connection groove 51 is arranged narrower than thediameter of the first bore 32 as well as the width of the rest of theoil-collecting recess 50 in view of the radial direction of the driveshaft 6. There are also provided an oil-supplying groove 52 and anoil-supplying aperture 53 on the side wall 13. The oil-supplying groove52 is connected to the oil-collecting recess 50 at approximately themiddle point thereof. The oil-supplying aperture 53 connects theoil-supplying groove 52 to the certain space 10 shown in FIG. 1.

Since stress concentration is likely to take place around the first bore32 under strong fastening power by the bolts 5, in this case, it may bedifficult in view of the strength required for the front housing 1 thatan oil-collecting recess 50 is formed being connected to all around thecircumference of the first bore 32 with a cutting process. According tothe second embodiment, however, the connection groove 51 connected withthe first bore 32 is arranged narrower than the diameter of the firstbore 32. Therefore, the stress concentration to be generated around thefirst bore 32 can be reduced.

FIG. 5 shows a lubricating oil feeding mechanism according to a thirdembodiment. In the third embodiment, component parts and elementscorresponding to those of the above first embodiment are indicated byidentical reference numerals, and a description thereof is omitted. Whatis different from the first embodiment is that a sub oil-collectingrecess 54 extends over two of the gaps 321 a, 321 b to connect the gap321 a to the gap 321 b. The sub oil-collecting recess 54 extends fromthe gap 321 a in the opposite direction of the extending direction ofthe oil-collecting recess 35 with respect to the gap 321 a. According tothe third embodiment, since the length of the sub oil-collecting recess54 becomes long, lubricating oil collecting ability on the side wallsurface 34 can be enhanced.

FIG. 6 shows a lubricating oil feeding mechanism according to a fourthembodiment. In the fourth embodiment, component parts and elementscorresponding to those of the above first embodiment are indicated byidentical reference numerals, and a description thereof is omitted.There is provided an oil-collecting recess 55 extending from a gap 321 cdefined by the first bore 32 and the shank portion 501 b of the bolt 5 cin the rotational direction of the drive shaft 6, the gap 321 c beingadjacent to the gap 321 a and being in the upper position with respectto the shaft seal 11 as the sliding part to be lubricated in the housingin an operating state of the mounted compressor. There are furtherprovided a first sub oil-collecting recess 56 and a second suboil-collecting recess 57 on the side wall 13. The first suboil-collecting recess 56 extends over two of the gaps 321 a, 321 c toconnect the gap 321 a to the gap 321 c, and has an arched shape. Thesecond sub oil-collecting recess 57 extends from the gap 321 a in theopposite direction of the rotation of the drive shaft 6. There isprovided an oil-supplying groove 58 which connects the oil-collectingrecess 55 to the oil-supplying aperture 41. The oil-supplying groove 58is arranged to be connected with the oil-supplying recess 55 at aforward position thereof in the rotational direction of the drive shaft6.

According to the fourth embodiment, lubricating oil adhered on the bolt5 a flows to the first sub oil-collecting recess 56 through the gap 321a. Also, lubricating oil adhered on the bolt 5 c flows to theoil-collecting recess 55 through the gap 321 c together with lubricatingoil flowing in the first sub oil-collecting recess 56. On the otherhand, the second sub oil-collecting recess 57 collects lubricating oiladhering on the side wall surface 34 and guides the lubricating oil tothe oil-collecting recess 55 through the gap 321 a, the first suboil-collecting recess 56 and the gap 321 c in turn. The oil-collectingrecess 55 as well as the first sub oil-collecting 56 can collectlubricating oil adhering on the side wall surface 34 as same as in thefirst embodiment described above.

Lubricating oil collected in the oil-collecting recess 55 is guidedalong the oil-supplying groove 58 and is led to the certain space 10shown in FIG. 1 through the oil-supplying aperture 41. Since the firstsub oil-collecting recess 56 is arranged over the gaps 321 a, 321 c,therefore, the lubricating oil collecting ability can be improved.Furthermore, since lubricating oil collected in the oil-collectingrecess 55 can be guided by the oil-supplying groove 58 only, lubricatingoil feeding mechanism can further be simplified.

The present invention may further be embodied in the following forms:

FIGS. 7A, 7B and 7C show some other lubricating oil feeding mechanismthan those described above, in that the relationship between anoil-collecting recess and an oil-supplying groove is modified. In themodification described below, component parts and elements correspondingto those of the above first embodiment are indicated by identicalreference numerals, and description thereof is omitted.

FIG. 7A shows an oil-collecting recess 59 extending from the gap 321 anot only in the rotational direction of the drive shaft 6 shown in FIG.1 but also downwardly in the radial direction of the drive shaft 6 so asto be sloped with respect to an oil-supplying groove 60. Furthermore,the oil-collecting recess 59 extends so that its width is substantiallythe same as the diameter of the first bore 32 along the longitudinaldirection of the oil-collecting recess 59. In addition, theoil-collecting recess 59 is formed so that its depth is substantiallythe same as that of the oil-supplying groove 60. The oil-supplyinggroove 60 is, at the middle point thereof, connected with theoil-collecting recess 59.

FIG. 7B shows an oil-collecting recess 61 extending from the gap 321 aand spreading over at the point of the connection between theoil-collecting recess 61 and an oil-supplying groove 64. Theoil-collecting recess 61 has an upper wall 62 and a lower wall 63, theupper wall 62 being formed straight and being connected to an upper wallof the oil-supplying groove 64, and the lower wall 63 being formed awayfrom the upper wall 62 as closing with the oil-supplying groove 64.

FIG. 7C shows an oil-collecting recess 65 extending from the gap 321 ain the rotational direction of the drive shaft 6 shown in FIG. 1 andbeing formed bent downwardly in the radial direction of the drive shaft6. There is provided an oil-supplying groove 66 extending to a forwardposition of the oil-collecting recess 65 in the radial direction of thedrive shaft 6.

In addition, it is possible to omit the sub oil-collecting recesses 39,40 in the first embodiment, and also possible to omit the suboil-collecting recess 57 in the fourth embodiment.

In the first embodiment, the oil-supplying grooves 37, 38 may beconnected to the oil-collecting recesses 35, 36 at approximately themiddle point thereof respectively.

In the first embodiment, it is not necessarily required to make theoil-supplying grooves 37, 38 deeper than the oil-collecting recesses 35,36. it may be implemented that both of the grooves 37, 38 and recesses35, 36 have the same depth.

In the fourth embodiment, in addition to the lubricating oil feedingmechanism described before, a first sub oil-collecting recess connectsthe gap 321 b to a gap 321 d which is in the upper position with respectto the shaft seal 11 as sliding part to be lubricated in the housing inan operating state of the mounted compressor. Also, a second suboil-collecting recess is connected to the gap 321 b, and anoil-collecting recess is connected to the gap 321 d, the oil-collectingrecess being connected to an oil-supplying groove. Although both ofthose mechanism are adopted together so as to collect lubricating oilgathered in the gaps 321 a, 321 b, 321 c and 321 d, only one of thedescribed mechanism might be used to improve the lubricativity.

In the fourth embodiment, the oil-supplying groove 58 is connected tothe sub oil-collecting recess 56. In this embodiment, the suboil-collecting recess 56 represents an oil-collecting recess, and theoil-collecting recess 55 represents a sub oil-collecting recess.

In each embodiment described above, the shape of each oil-collectingrecess 35, 36, 50 and 55, each sub oil-collecting recess 39, 40, 54 and56, and the connection groove 51 is formed arched. It may, however, bepossible to form each recess and the groove mentioned above to astraight shape or a wave shape.

The present invention may be embodied in compressors other than thecompressors of FIG. 1. For example, the present invention may beembodied in fixed displacement swash type compressor, double-headedpiston swash type compressor.

Finally, it will be understood by those skilled in the art that theforegoing description is of preferred embodiments of the disclosedinvention, and that various changes and modifications may be made to thepresent invention without departing from the spirit and scope thereof.

1. Lubricating oil feeding mechanism in a swash type compressor having:a housing comprising a plurality of housing elements, in which a swashplate chamber is formed for receiving a swash plate therein, and whichdefines a cylinder bore therein; a plurality of bolts arranged throughthe swash plate chamber and in through holes formed on a wall of thehousing for fastening the housing elements to form the housing; a driveshaft rotatably supported by the housing, the drive shaft being coupledto the swash plate; a piston accommodated in the cylinder bore so as todefine a compression chamber in the cylinder bore, the piston beingcoupled to the swash plate; and a suction chamber and a dischargechamber formed in the housing respectively, both being connectable tothe compression chamber; the lubricating oil feeding mechanismcomprising an oil-collecting recess and an oil-supplying groove formedrespectively on a side wall surface being defined on the wall of thehousing and facing the swash plate chamber, wherein the oil-collectingrecess connects a gap defined between the through hole and the bolt tothe oil-supplying groove, the gap being in the upper position withrespect to a sliding part to be lubricated in the housing in anoperating state of the mounted compressor, wherein the oil-collectingrecess extends from the gap in the circumferential direction of thedrive shaft, and wherein the oil-supplying groove extends upwardlytoward the oil-collecting recess, wherein the oil-supplying groove isarranged so that oil guided along the oil-supplying groove is led to thesliding part.
 2. Lubricating oil feeding mechanism according to claim 1,wherein the oil-collecting recess extends from the gap in the rotationaldirection of the drive shaft.
 3. Lubricating oil feeding mechanismaccording to claim 1, wherein the oil-collecting recess extends from thegap in the opposite direction of the rotational direction of the driveshaft.
 4. Lubricating oil feeding mechanism according to claim 1,wherein the oil-collecting recess has a connection groove as a partthereof, the connection groove connecting the gap to the rest of theoil-collecting recess, wherein the width of the connection groove isnarrower than the diameter of the through hole.
 5. Lubricating oilfeeding mechanism according to claim 1, wherein the oil-collectingrecess further extends downwardly from the through hole in an operatingstate of the mounted compressor.
 6. Lubricating oil feeding mechanismaccording to claim 1, wherein the oil-collecting recess extends so thatthe width of the oil-collecting recess is substantially the same as thediameter of the through hole along the longitudinal direction of theoil-collecting recess.
 7. Lubricating oil feeding mechanism according toclaim 1, further comprising a sub oil-collecting recess extending fromthe gap in the opposite direction of the extending direction of theoil-collecting recess with respect to the gap from which theoil-collecting recess extends.
 8. Lubricating oil feeding mechanismaccording to claim 7, wherein the sub oil-collecting recess extends overtwo of the gaps to connect the gaps to each other.
 9. Lubricating oilfeeding mechanism according to claim 1, wherein the oil-supplying grooveis formed deeper than the oil-collecting recess to promote oil flow fromthe oil-collecting recess to the groove.
 10. Lubricating oil feedingmechanism according to claim 1, wherein the oil-collecting recess has afirst oil-collecting recess and a second oil-collecting recess, thefirst oil-collecting recess extending from one of the gaps in therotational direction of the drive shaft, the second oil-collectingrecess extending from another one of the gaps in the opposite directionof the rotational direction of the drive shaft, wherein theoil-supplying groove has a first oil-supplying groove and a secondoil-supplying groove, the first oil-supplying groove being connected tothe first oil-collecting recess at a forward position in the rotationaldirection of the drive shaft with respect to the gap connected to thefirst oil-collecting recess, the second oil-supplying groove beingconnected to the second oil-collecting recess at a backward position inthe rotational direction of the drive shaft with respect to the gapconnected to the second oil-collecting recess.
 11. Lubricating oilfeeding mechanism in the swash type compressor according to claim 1,wherein the housing elements include a front housing in which theoil-collecting recess and the oil-supplying groove are formedrespectively, wherein the front housing supports the sliding part, andthe lubricating oil feeding mechanism includes a oil-supplying apertureformed in the front housing, wherein the oil-supplying aperture isconnected to the oil-supplying groove and extends toward the slidingpart so that oil guided along the oil-supplying groove and theoil-supplying aperture is led to the sliding part.
 12. Lubricating oilfeeding mechanism in the swash type compressor according to claim 11,the compressor having a shaft seal disposed between the front housingand the drive shaft to prevent refrigerant gas in the swash platechamber from leaking outside; wherein the sliding part is the shaftseal.